Buying a retina Macbook Pro to run windows is a very sensible solution considering that laptops with equivalent specs have 3-4 times the size and equal or worse battery life in lab tests according to PC Magazone. The hardware is not optimized for anything, it's a standard i7 3840QM processor, universal computer ram, univesal SSD and a standard 650 GT that's overclocked 12%.
Speed won't be a problem but battery life is. A decent Windows Notebook from Samsung, Lenovo, HP Elitebook,... can get the same low power consumption as OSX gets on the same hardware.
Apple's Windows drivers don't and even if there is no unswitchable GPU the cause.
http://www.phoronix.com/scan.php?page=article&item=apple_mac_power&num=1
That is an older test on a Mac mini with only a 9400M.
I frequently read notebookcheck reviews and the story is still the same. Good drivers offer the same minimum base power consumption. Apple's don't. The 650M constantly active will make it worse.
Windows is a bit more efficient in its GUI so the higher res might hurt it less or you won't even run it at native but still even 95W will not make up for all the downsides.
It is not as mobile under Windows.
Me personally I think the Touchpad sucks worst. Under Windows all you get is point click and two finger vertikal scroll and click. With a proper synaptic Windows notebook Touchpad you get multitouch gestures and there is even a driver for custom ones. Not with Apple's mediocre Windows touchpad drivers.
I would wait for Asus to release something similar. The UX31A/21A seem to show that a decent IPS big brother isn't that far off. With Windows 8 bringing better resolution independence to the table I think in a couple months you can buy a cheaper and better similar Windows notebook.
BTT just because there is no option doesn't mean it doesn't work. It is an odd resolution but somebody might just need to hack some config file to add it and the screen might support it just fine after that.
Personally I would run it at full res, adjust the DPI and put up with some odd apps. Complaining to developers about odd behaving apps or just switching to some that work fine is probably no such a big problem. Most of the important apps like office browsers, Adobe, VLC, should work just fine. I might be mistaken but usually it is the small rather unimportant stuff that shows problems.